Support animating <percentage> and <length-percentage> custom properties

third_party/WebKit/Source/core/animation/LengthInterpolationFunctions.cpp

Index: third_party/WebKit/Source/core/animation/LengthInterpolationFunctions.cpp
diff --git a/third_party/WebKit/Source/core/animation/LengthInterpolationFunctions.cpp b/third_party/WebKit/Source/core/animation/LengthInterpolationFunctions.cpp
index 1553826ba2d5f5a7a0f53dbfc341d5d5ba94a064..2dbbb20a5004dd8ff44ac4ffb5a80038411f7a85 100644
--- a/third_party/WebKit/Source/core/animation/LengthInterpolationFunctions.cpp
+++ b/third_party/WebKit/Source/core/animation/LengthInterpolationFunctions.cpp
@@ -213,8 +213,8 @@ const CSSValue* LengthInterpolationFunctions::createCSSValue(
 
   for (size_t i = 0; i < CSSPrimitiveValue::LengthUnitTypeCount; i++) {
     double value = toInterpolableNumber(*interpolableList.get(i)).value();
-    if (value == 0 ||
-        (i == CSSPrimitiveValue::UnitTypePercentage && !hasPercentage)) {
+    if (value == 0 &&
+        (i != CSSPrimitiveValue::UnitTypePercentage || !hasPercentage)) {
       continue;
     }
     CSSPrimitiveValue* currentValue =